The present invention relates to a vacuum cleaner, and particularly to a vacuum cleaner which is able to be used for water extraction cleaning and for dry suction cleaning.
An example of conventional dry and wet type vacuum cleaners enabling both water extraction cleaning and dry suction cleaning is disclosed in U.S. Pat. No. 4,218,805. The vacuum cleaner is of the upright-type which includes a main container having an open top closed by a top cover assembly with the interposition of either a reservoir if the cleaner is to be used for water extraction cleaning, or a dust filter assembly if it is to be used for dry suction cleaning. To facilitate separation of entrained liquid droplets from the incoming air when the vacuum cleaner is used for water extraction cleaning, a downwardly extending annular wall is provided in the interior of main container near an air inlet. In this arrangement, the incoming air is impinged against the surface of annular wall, so that heavy droplets can drop to be collected in the main container, while light air together with dust can rise up to a dust filter assembly. The rising air impinges against a downwardly inclining frusto-conical inner wall again, in order to separate any possibly entrained small droplets from the air. Although performing properly in the case of water extraction cleaning for carpet, such cleaner has a disadvantage of poor performance for water extraction cleaning for a smooth flat floor. Furthermore, splashing may be generated when droplets drop in the main container. Because the conical inner wall is arranged directly beneath the air outlet communicating with a motor and a suction device, the splashed small droplets may be entrained in the rising air again and then sucked into an impeller of the motor, thereby causing contaminated water to be discharged into the room.
The other example of conventional dry and wet type vacuum cleaners enabling both water extraction cleaning and dry suction cleaning is disclosed in EP 0245873. The cleaner is shown in FIGS. 15 and 16. As shown in the drawings, the cleaner 100 is of the horizontal-type which includes a chamber 103 disposed at the front and selectively receiving either a filter assembly 101 (FIG. 15) or a contaminated liquid container 102 (FIG. 16), and a motor 104 and a suction device at the rear. When the cleaner 100 is to be used for water extraction cleaning, air incoming into the cleaner 100 flows upwardly through a passage 105 upwardly extending to the liquid container 102 and impinges against the inner surface of upper wall 106 of liquid container 102, so that heavy droplets can drop to be collected in the liquid container 102, while light air together with dust can flow through an air passage 107 extending downwardly from its inlet near the upper wall 106 to the motor 104. However, such a conventional cleaner also has a disadvantage of poor performance for water extraction cleaning for a smooth flat floor, because of its design for water extraction cleaning for a carpet. Furthermore, there is a problem that droplets tend to come into the motor 104 through the air passage 107, since the inlet of air passage 107 is disposed near the inner surface of upper wall 106 against which droplets impinge. In this cleaner, the lower outlet 109 of the liquid detergent chamber 108, disposed beneath the contaminated liquid chamber 102, is connected with the liquid detergent inlet 110 provided at the bottom of chamber 103. If the connection becomes poor, there is a problem that liquid detergent leaks from the poor connection portion and undesirably collects on the bottom of chamber 103. In addition, operations for reversing from dry suction cleaning to water extraction cleaning or vice versa are troublesome.